Thread protector assembly comprising an open thread protector and an engageable closing cap

ABSTRACT

A thread protector assembly for protecting threads on the exterior end of a pipe as well as the interior. The assembly comprises an open protector and a closing cap that defines a completely closed plug that is engageable from above to cover over the open protector. The open protector has an internal thread and a bumper at an upper end with cutouts for applying a torque. The closing cap also has cutouts and internal ribs to engage the cutouts on the open protector and transmit torque to the open protector.

BACKGROUND OF INVENTION

1. Field of the Invention

An assembly for protecting threads on the end of a pipe as well asallowing access to the interior that comprises an open thread protector(1) which has an internal thread (3) and in an external periphery of itsupper end (4) a protective bumper (5) on which there are cutouts (6) forapplying a torque. A closing cap (2) acts as a completely closed plugand has a number of latches (8) located in the internal periphery of itslower end (7), which will deform to engage axially under the lower end(3′) of the open thread protector (1). A stopper plug (9) is formed onthe external periphery of the closing cap upper end (10), which alsoincludes cutouts for applying a torque (13) and internal ribs (11) totransmit torque to the cutouts (6) on the open protector. The innerradius of the closing cap (2) engages just slightly against the largestouter radius of open thread protector (1).

2. Brief Description of the Prior Art

Thread protectors protect threads on the end of a pipe and its interior.The present invention relates to an assembly that includes an openprotector and an engageable closing cap at the top that allows it toprotect the thread of a pipe during the various steps of the fabricationprocess, such as for example the passage of a drift, internal visualinspection, hydraulic testing and lacquering; also during its subsequenthandling and transport.

Documents U.S. Pat. No. 6,196,270 and U.S. Pat. No. 6,367,508 show knowndevices for protecting threads on the end of a pipe that include a baseportion from which there extends from one side axially a threaded boxwhose thread couples with the thread at the end of the tube, and on theother side an annular bumper that also extends axially from the base inthe direction opposite the box. Such protectors are made from anon-metallic raw material such as high-density polyethylene. The annularbumper has an internal taper such that the internal portion is conicaland can also include an external taper that extends from its middlepart.

Generally, known protectors currently are either of the open end type toallow workers to carry out maneuvering techniques and analysis duringmanufacture of the pipes; or of the closed type such as those citedabove, which are used to replace the open handling protectors for thepipe when shipped to an end user. Using first an open handling protectorand another that is closed for shipping involves greater raw materialuse for the same result, as well as an lengthening of the manufacturingtime for the pipes, because it requires changing from the openprotector, required for a hydraulic test and passage of a chuck, to aclosed type protector for shipping.

SUMMARY OF THE INVENTION

The invention solves the problems described above through an assemblythat combines both structures, that is, an open type protector and aclosed type protector. This is done through utilizing a threaded opentype protector which can be covered by a completely closed plug thatacts as an engageable closing cap. An easy placement of the plugoptimizes manufacturing times, and can be done at the same time. Theassembly is of low wall thickness and the use of raw materials isminimized. It also involves less generation of dangerous residues fromthe typical grease needed to apply and switch from an open protector.The open protector has dimensions that are optimized to allow maximumplant productivity during processing. The completely closed plug whichacts as an engageable closing cap adds resistance to front and sideimpact. The protector assembly is also totally recyclable, when it isformed of a material such as polyethylene polyprophylene, or polyamide.The assembly either can be re-used if it is in good shape upon removalor the plastic can be recycled to make a new protector. Any type ofthread or pipe can be used depending on customer requirements.

The assembly of the closing cap on the open threaded protector mustcomply with customer specifications as well as with ISO rule 11960Appendix I: “Thread Protector Design Validation Requirements”.

The object of this invention then is a protector set for the threadedend of a pipe and of its interior that comprises:

an open thread protector which has an internal thread and in an externalperiphery of its upper end a protective bumper on which there arecutouts for applying a torque; and a closing cap acts as a completelyclosed plug and has a number of latches located in the internalperiphery of its lower end which will deform to engage axially under alower end of the open thread protector; and

a stopper plug formed on the external periphery of the closing cap upperend, which also includes cutouts for applying a torque and internal ribsto transmit torque to cutouts on the open protector, wherein the innerradius of the completely closed plug engages only slightly against theouter radius of open thread protector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an cross-section, front explosion view of a closing cappositioned above an open thread protector according to the invention;and

FIG. 2 is a cross-sectional front view of an assembly, according to theinvention; and

FIG. 3 is an exterior, front perspective view of a closing cap assembledover the open thread protector.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Said assembly is made up of an open thread protector 1 and a closing cap2. Said open thread protector 1 includes an internal thread 3 that canbe coupled to the external thread of a pipe (not illustrated), and aprotective bumper 5 on the exterior periphery of its upper end 4, onwhich there are a number of cutouts for the protector's torque 6.

FIG. 1 illustrates in explosion view how the assembly for protectingthreads is to be attached to the end of a pipe (not illustrated). Anopen thread protector (1) has an internal thread (3) and in an externalperiphery of its upper end (4) that defines both a protective bumper (5)and cutouts (6) for applying a tightening or removing torque, so as toapply or remove the open thread connector from the pipe end. The openthread protector (1) as well as the closing cap (2) preferably aremanufactured from a non-metallic material, such as polyethylene,polypropylene or polyamide.

As shown by the cross-sectional assembly view of in FIG. 2, the closingcap (2) when in place over the open thread protector (10 acts as aremovable closing cap. Latches (8) located in the internal periphery ofits lower end (7), will deform to engage axially under the lower end(3′) of the open thread protector (1). A stopper plug (9) to close offthe interior of the pipe is formed on the external periphery of theclosing cap upper end (10), which also includes cutouts for applying atorque (13), with a wrench or the like. Internal ribs (11) on theclosing cap will transmit any applied torque to the cutouts (6) on theopen protector. The inner radius of the closing cap (2) engages againstthe outer radius of open thread protector (1).

Initial placement of the thread protector assembly can be by a clean andprecise axial blow from by a solid instrument such as a wooden mallet ormetal hammer. This clean blow initially places closing cap 2 over theopen protector 1, because from there it can be easily displaced. This isso because the only thing that makes friction on the open protector 1 isthe number of mechanical latches 8 of the closing cap 2. In principle,it is not necessary that the open protector 1 and the closing cap 2 bealigned to initiate placement. A gap 12 is generated between theinternal diameter of the closing cap 2 and the external diameter of theopen protector 1. During assembly of the unit, it is relatively easy torotate the closing cap 2 and to move it slightly forward to re-seat itand couple it with the inner protector torque cutouts 6. In case theassembly is not properly aligned, it is possible to rotate it slightlyand force it forward in such a way that it assembles normally. Once theunit is assembled on the end thread of a pipe, it is very difficult toremove it. Pipes are in contact with each other during handling, andwhile the gap 12 presents some risk of a small radial displacement ofthe closing cap 2 with respect to the open protector 1, if some of thelatches 8 are out of contact with the lower edge of the open protector1. If such radial displacement occurs, that still will not cause arelease of the plug 2, since a major contact is verified up to 180° ofany radial displacement.

FIG. 3 is an exterior, front perspective view of a closing cap assembledover the open thread protector. The protective bumper 9 and the torquecutouts 13 can be seen on the upper surface of the closing cap 2. Theinternal ribs 11 underneath are protected and inside the radius of theclosing cap 2, which only slightly engages a part of the outside of theopen thread protector 1, and the ribs can be rotated to engage insidethe open, inner protector torque cutouts 6.

In general, the wall thicknesses used for the protector assembly will bedetermined as in the prior art. In the illustrated embodiment, lateralwalls with a thickness of at least 2 mm are preferred for the openprotector 1 and closing cap 2 in order to resist lateral impact, and athickness or spacing of at least 8 mm between the protective bumpers 5and 9 in order to resist frontal impact.

While a preferred embodiment of the invention has been shown anddescribed, the invention is to be limited solely by the scope of theappended claims.

1. An assembly for protecting threads on the end of a pipe and allowingaccess to the interior thereof, comprising: an open thread protector (1)having an internal thread (3) and an external periphery proximate anupper end (4) that comprises a protective bumper (5) and cutouts (6) forapplying a torque to the protector; and a closing cap (2) which isadapted to engage over and upon the open thread protector and comprisesa number of latches (8) located proximate an internal periphery of itslower end (7), that are adapted to deform to engage axially under alower end (3′) of the open thread protector (1) when the inner surfaceof the closing cap (2) slightly engages against the outer surface ofopen thread protector (1); and the closing cap upper end (10) furthercomprises cutouts on its external periphery for applying a torque (13)to internal ribs (11) that are inside the outer radius of the openthread protector and are adapted to transmit torque to the cutouts (6)on the open protector.
 2. An assembly according to claim 1,characterized in that the open thread protector (1) and closing cap (2)are made from a non-metallic material, such as polyethylene,polypropylene or polyamide and the closing cap acts as a completelyclosed plug when inserted over the open thread protector.
 3. An assemblyaccording to claim 1, characterized in that latches (8) are equallyspaced around the internal periphery of lower end (7).
 4. An assemblyaccording to claim 1, characterized in that between internal surface ofthe closing cap (2) and the external surface of the open protector (1) aclearance space (12) is defined upon assembly that allows relativerotation between said open protector (1) and said closing cap (2).
 5. Anassembly according to claim 1, characterized in that a lateral wall ofthe closing cap (2) has a wall thickness of less than or equal to 2 mmto resist lateral impact, and a protective spacing of bumper (9) is lessthan or equal to 8 mm to resist any lateral, 45° or frontal impact. 6.An assembly according to claim 1, characterized in that said internalthread (3) is adapted to be axially coupled over the external thread ofa pipe end.